#include <vector>
#include <iostream>
#include <algorithm>

using namespace std;

// this is a functor
struct add_x {
  add_x(int x) : x(x) {}
  int operator()(int y) const { return x + y; }

private:
  int x;
};

ostream &operator <<(ostream &out,const vector<int> MyVector)
{ for(int idx=0;idx<MyVector.size();idx++)
	out << MyVector[idx] << " ";
  out << endl;
}

// Now you can use it like this:
int main()
{	add_x add42(42); // create an instance of the functor class
	int i = add42(8); // and "call" it
	cout << "i has value " << i << endl << endl;
        int myints[] = {16,2,77,29};
	vector<int> vals (myints, myints + sizeof(myints) / sizeof(int) );	
	vector<int> out(vals.size());
	cout << vals << endl;
	// Pass a functor to std::transform, which calls the functor on every element 
	// in the input sequence, and stores the result to the output sequence
	transform(vals.begin(), vals.end(), vals.begin(), add_x(1)); 
	cout << vals << endl;
	transform(vals.begin(), vals.end(), vals.begin(), add_x(5)); 
	cout << vals << endl;
	transform(vals.begin(), vals.end(), vals.begin(), add_x(-11)); 
	cout << vals << endl;
	transform(vals.begin(), vals.end(), vals.begin(), add42); 
	cout << vals << endl;
	cout << "Value to add to all elements >";
	int value;
	cin >> value;
	// Create a functor to add that value
	add_x add_val(value);
	transform(vals.begin(), vals.end(), vals.begin(), add_val); 
	cout << vals << endl;
	// Now pass a constructed functor each time
	transform(vals.begin(), vals.end(), vals.begin(), add_x(value*2)); 
	cout << vals << endl;
	// Store the value in a different vector, using an iterator to it.
	transform(vals.begin(), vals.end(), out.begin(), add_x(value*2)); 
	cout << out << endl;
}